- south-east Australia is prone to major bushfires in the summer months -
see history of bushfires
- bushfires can be grouped as:
- grass fires:
- relatively short-lived and lower intensity but fast moving fires
which may reach 18km/hour and catch people by surprise
- scrub fires:
- bushes and small multi-stemmed trees.
- the more litter there is on the ground to pre-heat the scrub
above, the more readily it will ignite.
- trunks of bushes and small trees will sustain an intense fire.
- tree trunks, logs and densely compacted litter sustain an intense
- fire can be carried through surface and elevated fuels like bark.
- severe fires may "crown" - spreading via tree tops.
- forest fires produce burning debris and embers.
- large fires make a sound like the roar of a passing train or jet
engine as they approach.
- fires need 3 main components, remove any one of them and the fire will
- fuel - this can be limited by controlled burn offs, by separating fuel
(eg. use of rakes to spread burning fuel), etc.
- oxygen - this can be limited by covering the fire
- heat - this can be reduced by adding water
- bush fires spread by 3 main modes:
- ember attack - wind blowing burning embers and debris ahead of a fire
- this is the usual mode of houses being burned, while spot fires can
form several kilometers ahead of the main fire.
- heat radiation - as the fire front approaches - heat radiation
decreases by the square of the distance to the fire.
- direct flame contact - a fire front usually takes about 10-20min to
- bush fires kill people mainly via:
- direct exposure to heat radiation
- exposed skin at the approach of a fire front
- survivability from radiant heat is said to be under threat at
distances within 4x the height of the fire
- ie. a 35m high forest fire blaze on an Australian bushfire day
may threaten life to those within 140m without protection.
- heat stroke (hyperthermia)
- asphyxiation from smoke
- car accidents - poor visibility, stress, falling trees, pedestrians
all combine to increase the danger.
- NB. other than fire fighters, most people who die in bushfires die
from the above causes before direct flames contact them.
Protecting yourself in a bushfire:
- avoid going to a region exposed to a bushfire or indeed to ANY forest
region on extreme hot, windy bushfire-prone days.
- avoid late evacuations from the region - it will probably be safer to stay
in a defendable house.
- whilst well prepared homes can usually be defended against most bush
fires, as Feb 2009 showed, in extreme conditions when bushfires develop in
conditions of ambient temperatures above 40degC in tinder-dry drought
conditions in forests and fanned by 100kph winds, the ferocity and speed of
the resultant fires are unlikely to allow homes in direct line of the fire
to be defendable reliably. Unfortunately in these extreme conditions, these
fires kill due to their rapid progression with limited warning (not even the
authorities may be aware) and houses and cars are not reliable refuges as
its no longer just a matter of fighting embers but the full brunt of fire
balls in a fire storm. The main survivors in the Marysville fire in 2009
survived by taking refuge in the middle of a sports oval, covering
themselves with woolen blankets to shield themselves from the radiant heat.
It would seem the best way to survive such extreme fires may be to have
concrete fire bunkers or cellars given early evacuation is unlikely to be a
feasible option, late evacuation likely to be fatal and defending the
house is certainly not a guarantee. Although many survived by being in cars
on cleared gravel areas or driving onto just burnt fields, many also died in
their cars in the panic of trying to get to safety at the last minute when
there is no visibility.
- if you are caught in a car during a bushfire:
- consider doing a U-turn to avoid the fire
- listen to radio ABC for news bulletins
- if you cannot get out of its way:
- pull off into a clearing so that there is minimal scrub/forest
fuel around you and you will be less likely to be hit by another car
- put your hazard lights on
- if possible find refuge in a solid building rather than being in a
car BUT once the fire is close DO NOT get out of the car and try to make a run for it, the
radiant heat will get you.
- close all doors, windows and vents
- cover up with wool/cotton clothing and rugs to protect yourself
from radiant heat
- get down low to minimise exposure to radiant heat via the windows.
- drink water to prevent dehydration and keep you cooler.
- remember, the fire front will usually pass within 10-20min.
Protecting your house in a bushfire:
- decide well before the bushfire season if your house is defendable or not
and develop a bushfire survival plan
- minimise risk to your house:
- clean up regularly to reduce fuel around the house - remove bush
litter, hazards and rubbish, keep bush, trees and grass away from
- keep roof gutters clear of leaves and debris
- don't use woodchip mulch around the house
- remove combustible items such as door mats, building materials,
wood heaps, fuel and paint cans, gas bottles.
- ensure chimneys can be closed
- ensure roof tiles and corrugated roofing are well fitting to
minimise ember entry into roof space.
- design house for fire-proofing and minimising risk to ember
- avoid exposed skylights
- breaks in roofline or complicated roof lines
- avoid dormer windows
- avoid exposed wood such as pergolas, timber decking,
unprotected windows and unpainted window sills
- avoid timber contacting the ground where embers may collect eg.
timber posts to ground level, timber stairs.
- avoid external recesses that promote collection of embers
- if it is not defendable then decide on EARLY evacuation, well before the
bushfire is a threat.
- late evacuation can be deadly.
- don't expect the fire brigade to be able to assist during the fire.
- if it is defendable and you decide to stay:
- remember most homes burn down long after the fire front has passed
- use the home to protect yourself during the fire front and at the same
time defend it.
- be alert, watch and listen if it is a Total Fire Ban in your
area or a bushfire is known to be nearby
- listen for weather forecasts and sirens and be on the lookout for
- you may receive little warning.
- ensure you have a good water supply and equipment to fight ember
- do not rely on mains water or mains power but use water from a
swimming pool or dam with a diesel or petrol fire fighting pump.
- buckets - preferably metal but plastic will do
- mops - especially old mops that hold a lot of water are great for
- hoses will need to reach all extremities of your home
- use metal tap fittings and put a hose fitting onto your washing
- 44 gallon (200L) drums, rubbish bins (eg. wheelie bins),
wheelbarrows, troughs or garden ponds filled with water placed
strategically around the home
- garden sprinkler systems can be used before the arrival of the
- consider roof-mounted sprinklers as long as you can get water to
- knapsack firefighting backpack that holds about 9L water and uses
- wet blankets to seal gaps under doors to prevent ember and smoke
- shovels and rakes to break up piles of burning material.
- downpipe or gutter plugs - buy them or use tennis balls,
stockings, sand and PVC pipes.
- ladders inside and outside to allow entry into roof space via man
- ensure you have adequate personal protective clothing:
- each person needs long trousers or overalls in natural fibre (eg.
jeans or cotton overalls), a long-sleeved shirt or jumper (cotton or
wool), broad-rimmed hat, sturdy leather boots, goggles, gloves, and
- cover all skin with a woollen blanket
- battery operated torches including one in the roof space.
- battery operated radio tuned to radio ABC.
- during the fire front:
- shelter from radiant heat inside the house away from windows and
regularly patrol the house looking for embers to put out.
- after the fire front has passed:
- go outside wearing your protective clothing and extinguish any